*{box-sizing:border-box}body{background:#f5f5f5;margin:0;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif}.app{background:#fff;flex-direction:column;max-width:430px;height:100vh;margin:auto;display:flex}.header{text-align:center;padding:20px}.header h1{margin:0;font-size:32px}.header p{color:#777;margin-top:8px}.divider{background:#ddd;height:1px}.chat-window{flex:1;padding:16px;overflow-y:auto}.message{border-radius:18px;max-width:75%;margin-bottom:12px;padding:12px 16px;line-height:1.5}.anna{background:#eee}.user{color:#fff;background:#007aff;margin-left:auto}.input-bar{border-top:1px solid #ddd;gap:10px;padding:16px;display:flex}.input-bar input{border:1px solid #ddd;border-radius:22px;flex:1;padding:12px;font-size:16px}.input-bar button{color:#fff;cursor:pointer;background:#007aff;border:none;border-radius:50%;width:50px;font-size:20px}.typing{color:#777;font-style:italic}.input-bar input:disabled{cursor:not-allowed;background:#f5f5f5}.input-bar button:disabled{opacity:.5;cursor:not-allowed}